First of the differance between high carbon alloy steel and the stuff they use in muzzle loader barrels [which grades between a forging and mild low carbon is tremendous.
Second the breach plug is only held in by threads which will shear under the right amount of stress. It is call a form of polish cannon.
Third the threads on the nipple are down right tiny, anipple in the eye at 1500fps will not make your day. Lee